/*
 * Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
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 */

package javax.swing.plaf;

import javax.swing.JList;
import java.awt.Point;
import java.awt.Rectangle;


/**
 * The {@code JList} pluggable look and feel delegate.
 *
 * @author Hans Muller
 */

public abstract class ListUI extends ComponentUI {

  /**
   * Returns the cell index in the specified {@code JList} closest to the
   * given location in the list's coordinate system. To determine if the
   * cell actually contains the specified location, compare the point against
   * the cell's bounds, as provided by {@code getCellBounds}.
   * This method returns {@code -1} if the list's model is empty.
   *
   * @param list the list
   * @param location the coordinates of the point
   * @return the cell index closest to the given location, or {@code -1}
   * @throws NullPointerException if {@code location} is null
   */
  public abstract int locationToIndex(JList list, Point location);


  /**
   * Returns the origin in the given {@code JList}, of the specified item,
   * in the list's coordinate system.
   * Returns {@code null} if the index isn't valid.
   *
   * @param list the list
   * @param index the cell index
   * @return the origin of the cell, or {@code null}
   */
  public abstract Point indexToLocation(JList list, int index);


  /**
   * Returns the bounding rectangle, in the given list's coordinate system,
   * for the range of cells specified by the two indices.
   * The indices can be supplied in any order.
   * <p>
   * If the smaller index is outside the list's range of cells, this method
   * returns {@code null}. If the smaller index is valid, but the larger
   * index is outside the list's range, the bounds of just the first index
   * is returned. Otherwise, the bounds of the valid range is returned.
   *
   * @param list the list
   * @param index1 the first index in the range
   * @param index2 the second index in the range
   * @return the bounding rectangle for the range of cells, or {@code null}
   */
  public abstract Rectangle getCellBounds(JList list, int index1, int index2);
}
